1. Field of the Invention
The invention relates to a link belt for use in a continuous furnace and, more particularly, link belts having roller configurations.
2. Background Art
It is known to advantageously treat various articles by subjecting the articles to high temperatures for preselected periods of time. Such treatment may, for example, effect sintering of articles which are made by compacting powdered refractory metals or ceramics. In this regard, some of these processes include method steps where the articles are transported through a heat treating zone in a furnace, rather than being loaded and unloaded in batches.
For example, it is known to transport articles through heating zones on link belts made of wire which are formed by conventional belt links. Somewhat similar to a wire belt is a transport belt disclosed in Miller, Jr. et al., U.S. Pat. No. 3,535,946 issued Nov. 15, 1995. The Miller, Jr. et al. patent discloses a belt made up of a succession of interwoven links, with each of the links formed of a length of tungsten wire which has been treated to a temperature of at least 400° C. The links are wound around an elliptical mandrel so as to provide, when cooled, a link which is in the form of a slightly flattened helix. Miller, Jr. et al. further disclose that they believe that by the avoidance of sharp bends in the link form and by the provision of a large number of interlocking contact points between links, strength and failure resistance are improved.
Autenrieth, et al. U.S. Pat. No. 5,199,868 issued Apr. 6, 1993 discloses a continuous furnace which serves for the simultaneous two-sided sintering of sintered sheets upon substrates. The furnace of Autenrieth, et al. includes a muffle and a conveyor belt longitudinally traversing the muffle and carrying the substrates. The belt consists of a pair of individual belts which are guided in parallel next to each other in a synchronous manner. The belt surfaces are mutually inclined at a small angle to the horizontal in the muffle. The substrates are self supporting between two parallel lateral edges. The substrates lie with one lateral edge on the belt surface of one belt and with the second lateral edge on the belt surface of the other belt. In this manner, the bottom side of each substrate does not touch the individual belts.
Fritsch, U.S. Pat. No. 2,994,917 issued Jul. 28, 1954 discloses an apparatus for converting metal powder into wrought metal shapes comprising at least one pair of oppositely disposed and laterally spaced vertical compactor elements. Each of the compactor elements includes an endless link belt mounted to travel about a pair of support wheels. The adjacent outer surfaces of the link belt form substantially continuous pressure surfaces inclined at an acute angle to the common axis of the pair of compactor elements. The adjacent pressure surfaces define a truncated V-shaped passageway. Means are provided for moving the link belt at the same rate of speed and in opposite directions so that the adjacent pressure surfaces travel uniformly toward the narrow end of the passageway defined by the compactor elements. In this manner, loose metal powder is compacted into a precompressed strip having sufficient mechanical strength to retain its form. This strip is introduced into a pair of pressure rolls. A power feed hopper is adapted to introduce loose metal powder into the wide end of the passageway. A pair of oppositely disposed pressure rolls having the axis of the rolls disposed in a horizontal plane define a roll gap with a width which is less than the width of the narrow end of the passageway.
Daringer, U.S. Pat. No. 5,558,204 issued Sep. 24, 1996 describes a weld-free belt assembly in which elongated length modules are coupled in widthwise and side-by-side relationships by transversely-oriented coupling modules. An internal cavity is defined within each link along with a surface configuration on each side of the link. This configuration defines an entry access portion for a coupler and slot portions for enabling relative longitudinal movement of the coupler, while retaining the coupler within the internal cavity. The interfitting coactions of the links and couplers enable an assembled belt to move from linear planar travel into a curved path so as to establish an endless belt configuration. Relative movement of the couplers within a link cavity enables longitudinal collection of links along the inner circumference when the belt enters a curvilinear travel path in approximately the same plane, and enables re-extension for return to linear travel. An assembled belt can be driven longitudinally by sprockets. Also, the belt can be driven along a serpentine path by lateral-edge dynamic frictional drive. Alternatively, a similarly driven and layered helical-path “carousel” arrangement can be used. Special configuration lateral-edge links provide protrusion-free lateral edge surfaces enabling smooth dynamic frictional drive along inner circumference surfaces during curvilinear travel.